Bacteria combined with gold to produce "living material"

Scientists at MIT are developing hybrid materials that are a cross between living bacterial cells and non-living components such as gold nanoparticles or quantum dots. The resulting "living materials" are able to respond to their environment like regular living cells, while also doing things like conducting electricity or emitting light.

The research team, which was led by assistant professor of electrical engineering and biological engineering Timothy Lu, started with E. coli bacteria. It was chosen because it normally produces a biofilm containing protein structures known as "curli fibers," which help the bacteria cling to surfaces.

By selectively adding peptides to the fibers, the scientists made it possible for them to bond with items such as gold nanoparticles that had been introduced to their environment. The resulting gold particle-covered fibers formed into rows of gold nanowires, that allowed the biofilm to conduct electricity. The scientists also succeeded in producing biofilms that were covered in quantum dots, which are nanocrystals composed of semiconductor materials.

Lu and his team were inspired by materials like bone, which contains both minerals and living cells, and that grows in response to environmental cues. It is hoped that once more fully developed, the technology could be used in the production of items such as self-healing materials, batteries, solar cells, diagnostic sensors, or scaffolds for tissue engineering.